Geostatistical analysis of resource islands under Artemisia tridentata in the shrub-steppe

Desert plants can influence the pattern of resources in soil resulting in small-scale enriched zones. Although conceptually simple, the shape, size, and orientation of these "resource islands" are difficult to study in detail using conventional sampling regimes. To demonstrate and alternative approach, we sampled soil under and around individual Artemisia tridentata (sagebrush), a dominant shrub of cool desert environments, and analyzed the samples with univariate statistics and geostatistics. Univariate statistics revealed that soil variables like total inorganic-N, soluble-C, and microbial biomass-C were distributed with highest mean values within about 25 cm of the plant axis and significantly lower mean values at distances beyond 60 cm. However, such simple analyses restricted our view of resource islands to identically sized, symmetrical accumulations of soil resources under each plant. Geostatistics provided additional information about spatial characteristics of soil variables. Variography revealed that samples separated by a distance of less than about 70 cm were correlated spatially. Over 75% of the sample variance was attributable to spatial variability. We modeled these spatial relationships and used kriging to predict values for unsampled locations. Resulting maps indicated that magnitude, size, and spatial distribution of soil resource islands vary between individual plants and for different soil properties. Maps, together with cross-variography, further indicate that resource islands under A. tridentata are not always distinguishable from the surrounding soil by sharp transition boundaries and may be asymmetrically distributed around the plant axis.     

Effects of myofibrogranuloma on serum calcium levels in walleye ( Stizostedion vitreum )

The effect of myofibrogranuloma (skeletal muscle degeneration) on serum calcium levels in spawning walleye ( Stizostedion vitreum ) was examined. Mean serum calcium levels for healthy male walleye (11.7 ± 1.5 mg/10 ml serum) was significantly lower ( P P < 0.1) in serum calcium were seen between healthy male and myofibrogranuloma-diseased male walleye (13.6 ± 2.1 mg/100 ml serum) and between healthy and myofibrogranuloma-diseased female walleye (20.2 ± 3.7 mg/100 ml serum). Elevations seen in mean serum calcium levels suggest the muscle degeneration and subsequent granuloma formation in later stages of myofibrogranuloma have a significant effect on serum calcium.     

Chromosomes of the lancelet,Branchiostoma floridae (order amphioxi)

Résumé Une étude des chromosomes deBranchiostoma floridae Hubbs, une espèce de lancelet de l'Atlantique occidentale, révéla la présence d'haplocaryons et diplocaryons au nombre de 19 et de 38 respectivement. Ces chromosomes furent comparés à ceux de 2 espèces de lancelets du Vieux Monde,Branchiostoma lanceolatum etB. belcheri. On résume les études concernant les chromosomes des Urochordata et des Agnatha et on émet des hypothèses sur las relations possibles entre les Protochordata et Agnatha.

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This research was supported by Samford University Research Fund, Grant No. 24, to Howell.     

Isolation of crystalline aldosterone from the urine of a nephrotic patient

Zusammenfassung Es ist erstmals gelungen, Aldosteron aus menschlichem Urin zu isolieren. Eine Fraktion des 13-Tage-Harnes von einem Knaben mit Nephrose und massiven Ödemen ergab 1,0 mg dieses biologisch hochaktiven Hormons in kristallisierter Form. Da der Gesamtgehalt gegen 3 mg betrug, stellt solcher Harn ein geeignetes Ausgangsmaterial dar zur extraktiven Gewinnung von Aldosteron. Letzteres erwies sich in seinen Eigenschaften als identisch mit Aldosteron aus Rinder-Nebennieren.     

The antimicrobial activity of citral

Zusammenfassung Bestätigung früherer Feststellungen, dass Citral eine antibakterielle Aktivität besitzt. Da Neral und Geranial (allein oder zusammen) jedoch wesentlich weniger aktiv sind, muss für die Citralaktivität eine bisher nicht identifizierte Substanz verantwortlich sein.     

Rates of ethiodide formation and the stereochemistry of ajmaline at C-21

Résumé Les auteurs ont mesuré les vitesses de réaction entre l'ajmaline plus dérivés et l'iodure d'éthyle. Les conclusions stéréochimiques deTaylor au C-21 en ont été confirmées.

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For previous papers on rates of quaternary iodide formation of alkaloids see (a)M. Shamma and J. B. Moss, J. Amer. chem. Soc.83, 5038 (1961) and (b)M. Shamma andE. F. Walker Jr., Chem. & Ind.1962, 1866.

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Acknowledgments. The authors wish to thank Dr.W. I. Taylor of CIBA Pharmaceutical Company for the generous gift of the compounds used in this study, and the National Institutes of Health (Grant No. GM-10608-01) for financial assistance.     

Pinitol,a larval growth inhibitor forHeliothis zea in soybeans

Summary A search for insect growth inhibitors in methanol extracts of soybean leaves resulted in isolation of pinitol. Pinitol caused a 50% reduction in weight gain (ED₅₀) ofHeliothis zea larvae at about 0.7% when added to a synthetic diet. Although myo-inositol is a normal component of the insect diet, it also caused growth inhibition at higher concentrations; ED₅₀4%.The authors are indebted to R.J. Molyneux for a reference sample of pinitol and to J. Baker for aid with the bioassay. Reference to a company and/or product named by the Department is only for purposes of information and does not imply approval or recommendation of the product to the exclusion of others which may also be suitable.     

Magnetic and photic responses in snails

Zusammenfassung Das Ausmass, in dem sich die SchneckeNassarius obsoleta asymmetrischem Licht zuwendet, ist einer früher beschriebenen Orientierungsreaktion übergeordnet, die selbst bei symmetrischer Beleuchtung eintritt. Ausserdem lässt diese Lichtreaktion eine physiologische Asymmetrie erkennen, die durch ein schwaches magnetisches Feld geändert werden kann.

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This study was aided by a grant from the National Science Foundation, No. G-15008, and by a contract between the Office of Naval Research, Department of Navy, and Northwestern University No. 1228-03.     

Effects of ethidium bromide in diploid and duplication strains of Aspergillus nidulans

Summary Unstable duplication and diploid strains of Aspergillus nidulans were treated with ethidium bromide, and it was shown that this drug reduces the number of sectors produced by such strains. The mechanisms which could be responsible for the partial stabilization of the strains are discussed and it is suggested that a similar mechanism is responsible for the production of sectors in both strains. It is also suggested that ethidium bromide could be useful for the reduction of instability of industrial strains.Acknowledgment. The authors are thankful to the National Council for the Development of Science and Technology (CNPq) for financial assistance.     

Increased liver calcium after calcium or milk gavage in rats

Summary For 1 or 2 h following a gavage of milk or 300 mM CaCl₂ (2 ml/100 g b.wt), rats had an increased liver calcium content when compared to rats receiving a deionized water gavage.Supported in part by a grant from the National Science Foundation (PCM 75-23603). We are grateful to Mr John O'Brien for his technical assistance.